An enum-declaration may optionally include a sequence of enum modifiers: enum-modifiers : enum-modifierenum-modifiersenum-modifierenum-modifier : newpublicprotectedinternalprivateIt is a compile-time error for the same modifier to appear multiple times in an enum declaration. The modifiers of an enum declaration have the same meaning as those of a class declaration (17.1.1). Note, however, that the abstract and sealed modifiers are not permitted in an enum declaration. Enums cannot be abstract and do not permit derivation.